Such a solid-state imaging element of a vertical spectral type is proposed to be capable of generating a plurality of color signals from one pixel region by laminating a plurality of photoelectric conversion portions (photodiodes (PDs), etc.) in a depth direction of a substrate.
The solid-state imaging element of the vertical spectral type has merits, for example, that a fake color is not easily generated because de-mosaic processing is not necessary and light utilization efficiency is higher than that of a solid-state imaging element in related art that generates a color signal of one of R, G, and B from one pixel region.
Hitherto, there is a technology for sharing a floating diffusion (FD) for realizing fine processing of a pixel with a plurality of pixels in the solid-state imaging element, and a configuration for sharing the FD with a plurality of pixels is proposed also to the solid-state imaging element of the vertical spectral type (for example, see PTL 1).
FIG. 1 shows an example of a configuration of the solid-state imaging element of the vertical spectral type sharing the FD with a plurality of pixels.
A solid-state imaging element 10 is a rear-surface irradiation type that light is incident from a rear-surface side (lower side in the diagram). A photoelectric conversion film (G) 12-1, which performs photoelectric conversion according to a wavelength of a G component of incident light, is formed in a pixel 1 of the solid-state imaging element 10 on the outside of a rear-surface of a Si substrate 11. A PD (B) 13-1 that performs photoelectric conversion according to a wavelength of a B component of the incident light and a PD (R) 14-1 that performs photoelectric conversion according to a wavelength of an R component of the incident light are laminated in order from the rear-surface side thereof in the Si substrate 11.
A vertical transistor (Tr) 16-1 is connected to the PD (B) 13-1. A planar Tr 17-1 is formed on a front-surface side (top side in the diagram) of the PD (R) 14-1.
Similarly, in a pixel 2, a photoelectric conversion film (G) 12-2 is formed on the outside of the rear surface of the Si substrate 11. A PD (B) 13-2 and a PD (R) 14-2 are laminated in order from the rear-surface side thereof in the Si substrate 11.
A vertical Tr 16-2 is connected to the PD 13-2. A planar Tr 17-2 is formed on a front-surface side of the PD (R) 14-2.
Further, an FD 15 is formed between the pixels. For example, an FD 15-2 is formed between the pixels 1 and 2.
In the pixel 1 of the solid-state imaging element 10, charges photoelectrically converted by the PD (B) 13-1 are transmitted and stored in the FD 15-2 via the vertical Tr 16-1, as shown by a solid arrow. Further charges photoelectrically converted by the PD (R) 14-1 are transmitted and stored in the FD 15-1 via the planar Tr 17-1.
Moreover, in the pixel 2, charges photoelectrically converted by the PD 13-2 (B) are transmitted and stored in an FD 15-3 via the vertical Tr 16-2. Further, charges photoelectrically converted by the PD (R) 14-2 are transmitted and stored in the FD 15-2 via the planar Tr 17-2.
That is, in the solid-state imaging element 10, the PD (B) 13-1 and the PD (R) 14-2 which are formed in different depths of the Si substrate 11 in the adjacent pixels 1 and 2 and have different wavelengths of light for photoelectric conversion, respectively, are configured to share the FD 15-2.